Hi,
I run into a crash with barebox master[1] when running the magicvar command.
The culprit seems to be 8 bytes of padding inserted between
__barebox_magicvar_start and OPTARG, the first array element:
0x0000000000061918 __barebox_magicvar_start = .
*(SORT_BY_NAME(.barebox_magicvar*))
=> *fill* 0x0000000000061918 0x8
.barebox_magicvar_OPTARG
0x0000000000061920 0x10 common/built-in.o
0x0000000000061920 __barebox_magicvar_OPTARG
The 8 byte *fill*er aligns the .barebox_magicvar_OPTARG section to 16 bytes.
Via addition and removal of dummy initcalls, we can shift the magicvars around
until we no longer straddle the 16 bit boundary:
0x0000000000061910 __barebox_magicvar_start = .
*(SORT_BY_NAME(.barebox_magicvar*))
.barebox_magicvar_OPTARG
0x0000000000061910 0x10 common/built-in.o
0x0000000000061910 __barebox_magicvar_OPTARG
Now running magicvar no longer crashes. We can achieve the alignment reliably by
adding . = ALIGN(16) at the start of the BAREBOX_MAGICVARS definition in
include/asm-generic/barebox.lds.h.
Does someone know what controls this 16 byte (or maybe 32 byte?) alignment?
Do we need to explicitly align the other linker array start symbols as well or
is there a better way?
Interestingly, the barebox_cmd array which I would've expected to behave the same
doesn't:
0x0000000000061638 __barebox_cmd_start = .
*(SORT_BY_NAME(.barebox_cmd*))
.barebox_cmd_2048
0x0000000000061638 0x8 commands/built-in.o
0x0000000000061638 barebox_cmd_2048
Here the 8 byte alignment is deemed ok by the linker...
Thoughts?
Cheers,
Ahmad
[1]: master at time of writing is 27ee6010 "console_simple: fix linking error when
ARCH_HAS_CTRLC enabled". To reproduce the issue I've added a single dummy initcall.
I can provide defconfig if requested.
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